Mr Leeson, 28, originally fought extradition to Singapore, but abruptly agreed last month to return to face 11 charges of forgery and fraud linked to his astronomical losses in trading derivatives tied to Japan's Nikkei stock index.
He was accompanied on the Singapore Airlines flight by his wife, Lisa, Stephen Pollard, his British lawyer, and the Singapore-based lawyer John Koh.
Mr Koh said Mr Leeson's first court appearance in Singapore was likely to be tomorrow and his trial could start before Christmas.
The former trader's departure from Frankfurt airport marked his return to the place where he was arrested on 2 March after a six-day international manhunt following the collapse of Barings, now taken over by ING Group of the Netherlands. He has since been held in a Frankfurt jail while German authorities decided on the extradition request.
Mr Leeson co-operated with UK investigators and sought a rival extradition bid from London, but the British authorities said the principal country of jurisdiction was Singapore.
He agreed to drop a final appeal and apologised for doubting he would get a fair trial in Singapore after the authorities there published a report into the Barings affair, spreading blame between him and his superiors.
Singapore legal officials also said that Mr Leeson probably faced substantially less than the maximum 14 years' jail. German authorities expect him to be given credit for his time in custody in Frankfurt.
Mr Leeson has pledged to cooperate with Singapore's investigation into the affair. But his lawyers have dismissed claims that he has agreed to a plea-bargain deal.